Ethylene / α-olefin copolymer with high light transmittance

Abstract

The present invention relates to an ethylene / α-olefin copolymer with high light transmittance, satisfying the following conditions (a) to (d): (a) the density is 0.855 g / cm3 to 0.885 g / cm3; (b) molecular weight distribution is 1.8 to 3.2; (c) a melt index is 0.3 g / 10 min to 40 g / 10 min under a load condition of 2.16 kg at 190°C; and (d) it is measured by high-temperature nuclear magnetic resonance carbon spectrum (13C-NMR) that the proportion of an ethylene ternary sequence EEE is less than 70%, and the proportion of EXE+XEX is greater than 10%, wherein E represents an ethylene unit, and X represents an α-olefin unit. The ethylene / α-olefin copolymer of the present invention has low glass transition temperature and high light transmittance, and can be used as a photovoltaic packaging material.

Description

High light transmittance ethylene / α-olefin copolymer Technical Field

[0001] The present invention relates to an ethylene / alpha-olefin copolymer with low glass transition temperature and high light transmittance and a preparation method thereof. Background Art

[0002] Affected by factors such as global warming and the continuous consumption of non-renewable energy, the global energy consumption structure is accelerating its transformation towards a low-carbon one. Photovoltaic power generation is clean and sustainable, and has become an important direction for the development of new energy, and is rapidly emerging in countries and regions around the world. As the market share of double-glass and N-type batteries continues to increase, the demand for polyolefin elastomer particles is experiencing rapid growth. Polyolefin elastomer POE is a thermoplastic elastomer that uses metallocene or non-metallocene catalysts to achieve in-situ polymerization of ethylene and α-olefins. It has excellent water vapor barrier properties, weather resistance, and high volume resistivity. It can ensure the safety of photovoltaic modules operating in high temperature and high humidity environments and long-term aging resistance, and is widely used in encapsulation film materials for photovoltaic modules.

[0003] The continuous improvement of photovoltaic module power generation efficiency requires more advanced battery technology on the one hand, and various auxiliary materials in the module to ensure better packaging performance and aging resistance on the other hand. Polyolefin elastomer is the packaging material in the module. The amount of sunlight absorbed by the cell through the packaging material directly determines the power generation of the cell, so transmittance is a key performance of the packaging material. For polymer materials, transmittance is closely related to factors such as crystallization performance. How to maximize the transmittance of the polymer while ensuring that other properties such as volume resistivity and yellowness meet the requirements is a very important issue. At the same time, for the packaging material, it is necessary to add a variety of small molecule additives when it is processed into packaging film in the later stage. Small molecule additives are very easy to decompose in the later stage, further affecting the transmittance of the film. Therefore, it is necessary to develop a polyolefin elastomer with high transmittance at the polymer particle end to improve the power generation performance of the module.

[0004] Summary of the Invention

[0005] The object of the present invention is to provide an ethylene / α-olefin copolymer having a low glass transition temperature and high light transmittance, which is suitable for use as an encapsulation film material for photovoltaic modules.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] An ethylene / α-olefin copolymer, satisfying the following conditions (a) to (d):

[0008] (a) Density is 0.855 g / cm 3 to 0.885g / cm 3 ;

[0009] (b) a molecular weight distribution of 1.8 to 3.2;

[0010] (c) a melt index of 0.3 g / 10 min to 40 g / 10 min at 190° C. and 2.16 kg load; and

[0011] (d) By carbon nuclear magnetic resonance spectroscopy ( 13 C-NMR) measured that the proportion of ethylene ternary sequence EEE was <70%, and the proportion of EXE+XEX was >10%;

[0012] Here, E represents an ethylene unit, and X represents an α-olefin unit.

[0013] In the present invention, preferably, the melt index of the ethylene / α-olefin copolymer is 0.5 g / 10 min to 30 g / 10 min.

[0014] In the present invention, preferably, the proportion of the ethylene ternary sequence EEE of the ethylene / α-olefin copolymer is 60.3% to 69.5%, the proportion of EXE is 9.5% to 11.8%, and the proportion of XEX is 1.2% to 1.82%.

[0015] In the present invention, preferably, the proportion of the ethylene ternary sequence EEE of the ethylene / α-olefin copolymer is 63.5% to 69.5%, the proportion of EXE is 9.5% to 11.8%, and the proportion of XEX is 1.2% to 1.8%.

[0016] In the present invention, the melting temperature of the ethylene / α-olefin copolymer is 75° C. or lower. Specifically, the melting temperature may be 50° C. or higher, 55° C. or higher, or 60° C. or higher, and may be 70° C. or lower, 68° C. or lower, or 65° C. or lower.

[0017] In the present invention, the glass transition temperature (Tg) of the ethylene / α-olefin copolymer is below -45°C. Specifically, the glass transition temperature may be below -50°C, below -55°C, or below -60°C.

[0018] In the present invention, the weight average molecular weight Mw of the ethylene / α-olefin copolymer is 40,000 g / mol to 150,000 g / mol. Specifically, the weight average molecular weight may be 45,000 g / mol or more, 60,000 g / mol or more, or 70,000 g / mol or more, and may be 150,000 g / mol or less, or 80,000 g / mol or less.

[0019] In the present invention, the number average molecular weight Mn of the ethylene / α-olefin copolymer is 20,000 g / mol to 80,000 g / mol. Specifically, the number average molecular weight may be 25,000 g / mol or more, 30,000 g / mol or more, or 40,000 g / mol or more, and may be 80,000 g / mol or less, 60,000 g / mol or less, or 50,000 g / mol or less.

[0020] The weight average molecular weight (Mw) and number average molecular weight (Mn) are polystyrene equivalent molecular weights analyzed by gel permeation chromatography (GPC). The molecular weight distribution can be calculated from the ratio of Mw / Mn.

[0021] In the present invention, the α-olefin of the ethylene / α-olefin copolymer is an olefin having 3 to 20 carbon atoms, including one or more of propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene and 1-eicosene.

[0022] In the present invention, the molar insertion ratio of the α-olefin comonomer of the ethylene / α-olefin copolymer is 5% to 50%. Specifically, the molar insertion ratio may be greater than 10%, greater than 15%, or greater than 20%, and may be less than 50%, less than 45%, or less than 40%.

[0023] The present invention also relates to a method for preparing the above ethylene / α-olefin copolymer.

[0024] The method for preparing the ethylene / α-olefin copolymer of the present invention comprises: polymerizing ethylene and α-olefin in the presence of a catalyst composition comprising compound A and compound B;

[0025] The ethylene / α-olefin copolymers of the present invention are prepared using transition metal compounds represented by Compound A and Compound B as catalysts. Compounds A and B have different polymerization activities and temperature resistance for α-olefin monomers. Therefore, when these two compounds are mixed, different process parameters can be adjusted as needed to develop different copolymers.

[0026] In the present invention, the molar ratio of the transition metal compound represented by compound A and compound B can be 1:1 to 1:10, for example, 1:1.5 to 1:9, 1:2 to 1:5, or 1:2 to 1:4, but is not limited thereto. The total amount of the catalyst can be determined by those skilled in the art based on the catalyst activity and the weight of the target product.

[0027] To produce copolymers with excellent light transmittance, we discovered three approaches: first, using transition metal compounds A and B with varying comonomer copolymerization abilities; second, repeatedly adjusting the flow rate ratio of ethylene to comonomer and the flow rate ratio of the mixed transition metal compounds to achieve a more uniform comonomer insertion rate; and third, using multiple comonomers for simultaneous polymerization, controlling the flow rate ratios of the different comonomers to achieve varying degrees of disruption to the ethylene crystalline segments. In this invention, these three approaches were combined to produce a copolymer with excellent light transmittance.

[0028] In the present invention, in order to make the compound A and / or compound B have higher polymerization activity, a co-catalyst is preferably used in the catalyst composition. The co-catalyst is divided into two categories: alkyl aluminum or alkyl aluminoxane compounds, and borate compounds. Specifically, the alkyl aluminum or alkyl aluminoxane compounds include trimethyl aluminum, triethyl aluminum, triisobutyl aluminum, tripropyl aluminum, tributyl aluminum, methyl aluminoxane (MAO), modified methyl aluminoxane (MMAO), ethyl aluminoxane, isobutyl aluminoxane or tert-butyl aluminoxane; the borate compounds include trimethyl ammonium tetraphenyl borate, methyl dioctadecyl ammonium tetraphenyl borate, triethyl ammonium tetraphenyl borate, tripropyl ammonium tetraphenyl borate, tri (n-butyl) ammonium tetraphenyl borate, methyl tetradecyl octadecyl ammonium tetraphenyl borate, N,N-dimethylanilinium tetraphenyl borate, N,N -Diethylanilinium tetraphenylborate, N,N-dimethyl (2,4,6-trimethylanilinium) tetraphenylborate, trimethylammonium tetrakis (pentafluorophenyl) borate, methyl ditetradecyl ammonium tetrakis (pentafluorophenyl) borate, methyl dioctadecyl ammonium tetrakis (pentafluorophenyl) borate, triethylammonium tetrakis (pentafluorophenyl) borate, tripropylammonium tetrakis (pentafluorophenyl) borate, tri(n-butyl)ammonium tetrakis (pentafluorophenyl) borate, tri(sec-butyl)ammonium tetrakis (pentafluorophenyl) borate, N,N-dimethylanilinium tetrakis (pentafluorophenyl) borate, N,N-diethylanilinium tetrakis (pentafluorophenyl) borate, N,N- Dimethyl (2,4,6-trimethylanilinium) tetrakis (pentafluorophenyl) borate, trimethylammonium tetrakis (2,3,4,6-tetrafluorophenyl) borate, triethylammonium tetrakis (2,3,4,6-tetrafluorophenyl) borate, tripropylammonium tetrakis (2,3,4,6-tetrafluorophenyl) borate, tri(n-butyl)ammonium tetrakis (2,3,4,6-tetrafluorophenyl) borate, dimethyl (tert-butyl)ammonium tetrakis (2,3,4,6-tetrafluorophenyl) borate, N,N-dimethylanilinium tetrakis (2,3,4,6-tetrafluorophenyl) borate, N,N-diethylanilinium tetrakis (2,3,4,6-tetrafluorophenyl) borate borate or N,N-dimethyl-(2,4,6-trimethylphenylammonium)tetrakis-(2,3,4,6-tetrafluorophenyl)borate, a trisubstituted ammonium salt type borate compound such as dioctadecylammoniumtetrakis(pentafluorophenyl)borate, ditetradecylammoniumtetrakis(pentafluorophenyl)borate or dicyclohexylammoniumtetrakis(pentafluorophenyl)borate, a trisubstituted phosphate type borate compound such as triphenylphosphoniumtetrakis(pentafluorophenyl)borate, methyldioctadecylphosphoniumtetrakis(pentafluorophenyl)borate or tris(2,6-dimethylphenyl)phosphoniumtetrakis(pentafluorophenyl)borate, etc., but are not limited thereto;

[0029] The molecular weight distribution of the ethylene / α-olefin copolymer prepared by using an appropriate amount of these cocatalysts is more uniform and the polymerization activity is higher. In some specific embodiments, the ratio of the cocatalyst feed rate to the catalyst feed rate is 5-1000, preferably 10-100, based on the molar ratio of the metal.

[0030] In the present invention, under the conditions of the catalyst composition, by continuously passing 1cm -3 / min to 80cm -3 / min hydrogen inhibits the polymerization reaction, specifically, the hydrogen introduction rate is 1cm -3 / min or above or 5cm -3 / min or above or 10cm -3 / min or above or 20cm -3 / min or above or 30cm -3 / min or more, and 80cm -3 / min or less or 60cm -3 / min or less or 50cm -3 / min or less or 40cm -3 / min or less.

[0031] In the present invention, the polymerization reaction can be carried out at a temperature of 100°C to 200°C to ensure that the catalyst composition maintains high polymerization activity at a suitable temperature. Specifically, the polymerization reaction temperature can be 100°C, 120°C, 140°C, 160°C, 180°C, or 200°C, but is not limited to these temperatures.

[0032] In the present invention, the polymerization reaction can be carried out at a pressure of 1 MPa to 7 MPa to ensure that the catalyst composition maintains a high polymerization activity under a suitable pressure. Specifically, the polymerization reaction pressure can be carried out at a pressure of 1 MPa, 3 MPa, 5 MPa, 6 MPa, or 7 MPa, but is not limited thereto.

[0033] In the present invention, compound A is further described in Chinese patent CN 111484574 A, which is incorporated herein by reference, and has the structure of the following formula I:

[0034] In the formula I, R1 and R2 are the same or different and are independently selected from hydrogen, methyl, isopropyl, and tert-butyl. Preferably, R1 is selected from methyl, isopropyl, and tert-butyl, and R2 is selected from hydrogen, methyl, and tert-butyl; M is selected from titanium, zirconium, or hafnium, preferably zirconium;

[0035] Preferably, compound A in the present invention has the following structure:

[0036] Compound B is further described in Chinese Patent No. CN 111909196 B, which is incorporated herein by reference, and has the structure of Formula II below:

[0037] In Formula II, R3 is selected from the following groups: C3-10 cycloalkyl, C3-10 cycloalkyloxy, C3-10 dicycloalkylamino, C6-14 aryl, C6-14 aryloxy, C6-14 arylamino, dicyclohexylmethyl, dibenzocycloheptyl, anthracenyl, dicyclohexaphenyl; R4 is selected from hydrogen, halogen, or the following groups: C1-6 alkyl, C1-6 alkoxy, C3-10 cycloalkyl, C3-10 cycloalkyloxy, C6-14 aryl, C6-14 aryloxy; T1 and T2 are the same or different and are both 1,2-ethylene, 1,3-propylene, 1,4-butanediyl, 2,4-pentanediyl; X is halogen, methyl, benzyl, or dimethylamino; M is selected from titanium, zirconium, or hafnium, preferably zirconium;

[0038] Preferably, compound B in the present invention has the following structure:

[0039] A large amount of α-olefin comonomer is inserted into the molecular chain of the ethylene / α-olefin copolymer of the present invention, which is prepared by using these mixed compounds as catalysts. The α-olefin comonomer is distributed both in high-density areas similar to polyethylene segments and in large quantities between the ethylene monomers. This distribution destroys the crystallization of the polyethylene segments, making the lamellae size of the copolymer smaller and more uniform, and having better light transmittance.

[0040] Typically, when using solution polymerization to polymerize two or more non-polar monomers, the molecular weight distribution broadens, which improves the polymer's processing properties, but also reduces some mechanical properties. Molecular weight distribution is affected by the catalyst's copolymerization properties with different monomers. When two or more catalysts are used to prepare copolymers, if the polymerization properties of each catalyst vary significantly, the molecular weight distribution of the polymer may become broadened.

[0041] To control the molecular weight of the polymer and maintain good processing properties, a certain amount of hydrogen must be introduced at the appropriate time during the polymerization reaction to prevent the generation of β-hydrogen elimination reactions on the polymer chain and terminate the polymerization reaction. In this case, the molecular weight of the polymer decreases and the melt index increases. Therefore, it is necessary to determine the appropriate catalyst type and hydrogen introduction amount within a range that satisfies both the inherent characteristics of the catalyst structure affecting molecular weight and molecular weight distribution and the molecular weight reduction effect of hydrogen introduction.

[0042] Generally, if the crystallinity distribution of a copolymer is high, the transmittance decreases and the glass transition temperature increases due to the increase in the high crystallinity content. In contrast, the copolymer of the present invention has a narrower lamellae size distribution index and a more uniform lamellae distribution, thereby having excellent transmittance and low-temperature resistance.

[0043] The present invention also relates to the use of the above ethylene / α-olefin copolymer.

[0044] The ethylene / α-olefin copolymer of the present invention can be combined with a crosslinking agent, a crosslinking aid, a silane coupling agent, a light stabilizer, an ultraviolet absorber, an anti-precipitation aid, an anti-PID aid, and other auxiliary agents to form a resin composition. In addition to the above-mentioned components, various additives known in the art can be appropriately included depending on the application of the applicable resin component.

[0045] In addition, the resin composition can be used to prepare photovoltaic encapsulation materials through molding methods such as cast extrusion and twin-screw extrusion, for example, to make encapsulation films in photovoltaic modules to ensure that the solar cells have long-term stable power generation performance. Beneficial effects:

[0046] The ethylene / α-olefin copolymer of the present invention exhibits a low EEE ternary structure and a more uniform α-olefin distribution. The uniform insertion of the α-olefin increases the destruction of ethylene crystalline segments, weakening the polymer's crystallization properties. This results in thinner lamellae, a narrower lamellae size distribution index, and a more uniform lamellae distribution. Consequently, the copolymer exhibits lower crystallinity. Polymers with low crystallinity have higher transparency and, in photovoltaic encapsulation films, can increase the intensity of sunlight incident on the cell surface, thereby improving the cell's power generation efficiency. Furthermore, polymers with low crystallinity have a lower glass transition temperature, allowing the product to maintain excellent deformation resistance at lower temperatures, ensuring the long-term use of battery modules in even colder environments. DETAILED DESCRIPTION

[0047] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts are within the scope of protection of the present invention.

[0048] Catalysts used in the examples and comparative examples:

[0049] Compound A:

[0050] Compound B:

[0051] Modified methylaluminoxane (MMAO): concentration 7 wt% Al, Isopar E solvent, Nouryon Chemicals (Ningbo) Co., Ltd.

[0052] Example 1

[0053] Solution polymerization was carried out in a 10L continuous tank reactor, with feed from the bottom and discharge from the top. The solvent Isopar E was introduced at a rate of 40 kg / h. Comonomers (octene, hexene, butene) and ethylene were continuously fed to the reactor at the feed rates shown in Table 1 after deoxygenation and dehydration in a fixed bed. The catalyst and cocatalyst MMAO were formulated into a solution and fed to the reactor at the feed rates shown in Table 1. The catalyst concentration was 400 ppm (dissolved in Isopar E solvent). The reaction was controlled at the specified temperature by the reactor preheat exchanger and reactor jacket, and the pressure was controlled by a pneumatic proportional control valve at the reactor discharge port.

[0054] After the polymerization reaction is completed, the melt is devolatilized and granulated and then sampled for analysis;

[0055] Other parameters are shown in Table 1;

[0056] In Examples 2 to 4, copolymers with different properties were prepared by changing parameters such as the type of inserted comonomer, flow rate ratio, and catalyst introduction amount. The parameters are shown in Table 1.

[0057] The unit of catalyst flow rate is μmol·min -1 The flow rate of the co-catalyst is in mmol·min -1 .

[0058] Comparative Examples 1-4

[0059] The copolymer was prepared by solution polymerization using a method substantially the same as in Example 1, except that the process parameters were adjusted. In particular, rac-ethylene bis(1-indenyl) zirconium dichloride (referred to as catalyst C) was 99%.

[0060] Table 1 Some materials and process parameters of Examples 1-4 and Comparative Examples 1-4 Note: C2, C4, C6, and C8 represent ethylene, butene, hexene, and octene, respectively;

[0061] The catalyst feed rate is based on metal.

[0062] Performance characterization of ethylene / α-olefin copolymers:

[0063] The properties of the ethylene / α-olefin copolymers prepared in the examples and comparative examples were measured by the following methods, and the results are shown in Table 2:

[0064] (1) Density (g / cm3 ) was measured according to ASTM D-792.

[0065] (2) Melt index (g / 10 min) was measured according to ASTM D-1238 (conditions: 190° C., 2.16 kg load).

[0066] (3) The glass transition temperature (°C) can be measured using a differential scanning calorimeter (DSC 6000) manufactured by PerkinElmer. Specifically, under a nitrogen atmosphere, the temperature of the copolymer is raised to 150°C using DSC and maintained for 5 minutes. The temperature is then cooled to -100°C, and the temperature is raised again, and the DSC curve is observed. The heating rate and cooling rate are both 10°C / min.

[0067] (4) Molecular weight (Mw), molecular weight distribution (MWD), and comonomer insertion rate can be obtained using gel permeation chromatography (GPC). Specifically, column: Agilent Olexis; solvent: trichlorobenzene; flow rate: 1.0 ml / min; sample concentration: 1.0 mg / ml; injection volume: 200 μl; column temperature: 160°C; detector: Agilent High Temperature RI detector; standard: polystyrene (corrected using a cubic function).

[0068] (5) Comonomer distribution can be utilized 13C NMR measurements were performed. Specifically, 2.74 g of sample and tetrachloroethane-d2 containing 0.025 M Cr(AcAc)3 were added to a Nore II 1001-7 10 mm NMR tube. Oxygen was removed by manually purging the tube with nitrogen for 1 minute using a Pasteur pipette. The tube and its contents were heated to ~150°C using a heating block, minimizing the use of a heat gun, to dissolve and homogenize the sample. The sample was thoroughly mixed immediately before analysis and not allowed to cool before being inserted into the heated NMR probe. This is necessary to ensure that the sample is homogeneous and representative of the entire sample. Data were collected using a Bruker 400 MHz spectrometer equipped with a Bruker cryoprobe. Data were collected using 160 scans, a 6 second pulse repetition delay, and a sample temperature of 120°C. All measurements were performed on a non-spinning sample in lock mode. The sample was allowed to thermally equilibrate for 7 minutes before data acquisition. 13 The C NMR chemical shifts are relative to the EEE ternary sequence segment absorption peak at 30.0 ppm. For the butene comonomer, the chemical shifts at 39.7 ppm, 26.7 ppm, and 11.2 ppm correspond to the ternary sequence segment absorption peaks of EBE, and the chemical shift at 34.7 ppm corresponds to the ternary sequence segment absorption peak of BEB; for the hexene comonomer, the chemical shifts at 38.1 ppm, 34.1 ppm, 29.5 ppm, 23.4 ppm, and 14.1 ppm correspond to the ternary sequence segment absorption peaks of EHE, and the chemical shift at 35.0 ppm corresponds to the ternary sequence segment absorption peak of HEH; for the octene comonomer, the chemical shifts at 38.5 ppm, 32.4 ppm, 22.9 ppm, and 14.1 ppm correspond to the ternary sequence segment absorption peaks of EOE, and the chemical shift at 35.1 ppm corresponds to the ternary sequence segment absorption peak of OEO. The proportion of the sum of the EBE, EHE, and EOE ternary sequences in the molecular chain is taken as the proportion of EXE, and the proportion of the sum of the BEB, HEH, and OEO ternary sequences in the molecular chain is taken as the proportion of XEX.

[0069] Table 2 Properties of ethylene / α-olefin copolymers prepared in Examples 1-4 and Comparative Examples 1-4

[0070] Preparation of encapsulating film

[0071] A certain amount of the ethylene / α-olefin copolymers prepared in the Examples and Comparative Examples were weighed and thoroughly absorbed with a crosslinker, a crosslinking aid, a silane coupling agent, a light stabilizer, a UV absorber, an antioxidant, and an anti-PID agent before being added to a single-screw cast film extruder. The mixture was melted and plasticized, then injected into a T-die. After melt extrusion, film casting, cooling, slitting, and winding, a photovoltaic encapsulation film was produced. The ingredients of the encapsulation film are shown in Table 3.

[0072] Table 3 Composition and dosage of the encapsulation film

[0073] The transmittance test was carried out according to the spectrophotometer method of GB / T 2410-2008, and the average values ​​in the wavelength ranges of 290nm to 380nm and 380nm to 1100nm were calculated respectively. The results are shown in Table 4.

[0074] Table 4 Transmittance of the encapsulation films prepared in Examples 1-4 and Comparative Examples 1-4

[0075] The results show that light transmittance is closely related to the comonomer insertion rate and the ratio of ternary sequence monomers. The present invention uses multiple methods to control the preparation of ethylene-α-olefin, resulting in polymers with high light transmittance, which can meet the requirements of maintaining high power generation efficiency in photovoltaic modules.

Claims

1. An ethylene / α-olefin copolymer, characterized in that: The proportion of ethylene ternary sequence EEE was <70% and the proportion of EXE+XEX was >10% as measured by C NMR spectroscopy; Here, E represents an ethylene unit, and X represents an α-olefin unit.

2. The ethylene / α-olefin copolymer according to claim 1, characterized in that The proportion of ethylene ternary sequence EEE is 63.5% to 69.5%, the proportion of EXE is 9.5% to 11.8%, and the proportion of XEX is 1.2% to 1.8%.

3. The ethylene / α-olefin copolymer according to claim 1 or 2, characterized in that The proportion of ethylene ternary sequences EEE is 60.3% to 69.5%, EXE is 9.5% to 11.8%, and XEX is 1.2% to 1.82%.

4. The ethylene / α-olefin copolymer according to any one of claims 1 to 3, characterized in that The following conditions are also met: (a) Density: 0.855 g / cm 3 Up to 0.885g / cm 3 ; (b) a molecular weight distribution of 1.8 to 3.2; (c) The melt index at 190° C. and a load of 2.16 kg is 0.3 g / 10 min to 40 g / 10 min, preferably 0.5 g / 10 min to 30 g / 10 min.

5. The ethylene / α-olefin copolymer according to any one of claims 1 to 4, characterized in that The melting temperature is 75°C or less.

6. The ethylene / α-olefin copolymer according to any one of claims 1 to 5, characterized in that The glass transition temperature is below -45°C.

7. The ethylene / α-olefin copolymer according to any one of claims 1 to 6, characterized in that The weight average molecular weight Mw is 40000 g / mol to 150000 g / mol.

8. The ethylene / α-olefin copolymer according to any one of claims 1 to 7, characterized in that The number average molecular weight Mn is 20000 g / mol to 80000 g / mol.

9. The ethylene / α-olefin copolymer according to any one of claims 1 to 8, characterized in that The α-olefin is an olefin having 3 to 20 carbon atoms.

10. The ethylene / α-olefin copolymer according to any one of claims 1 to 9, characterized in that The α-olefin includes at least one of propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene and 1-eicosene.

11. The ethylene / α-olefin copolymer according to any one of claims 1 to 10, characterized in that: The molar insertion rate of the α-olefin comonomer is 5% to 50%.

12. The ethylene / α-olefin copolymer according to any one of claims 1 to 11, characterized in that The molar insertion rate of the α-olefin comonomer is 10% to 20%.

13. A photovoltaic encapsulation material comprising the ethylene / α-olefin copolymer according to any one of claims 1 to 12.

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